青岛霾天气下大气汞的污染特征分析

2013年1月14~17日青岛市经历了一次大范围的霾污染过程,采集并测定大气气态汞和颗粒态汞,研究汞的污染特征.结果表明,气态汞(TGM)的平均浓度为(2.8±0.9)ng/m3,颗粒汞(PHg)的平均浓度为(245±174)pg/m3.在霾发生的14、15日PHg/TSP的比值明显高于16、17日,且TGM与PHg浓度呈负相关关系,霾日气象条件有利于TGM向PHg转化.大气汞浓度与温度、相对湿度正相关,与风速负相关.TGM与SO2、NO2显著正相关,化石燃料的燃烧是大气汞的主要来源.对大气气团的后向轨迹进行聚类分析,将其分为5类,霾日大气中的汞主要来自近距离传输,受山东本地污染影响,气态汞含量最高.

The characteristic analysis of atmospheric mercury during haze days in Qingdao

In order to investigate the characteristics of atmospheric mercury pollution, total gaseous mercury (TGM) and particulate mercury (PHg) samples were collected in Qingdao during January 14-17, 2013, when a serious haze event occurred. The results showed that the average concentrations of TGM and PHg in Qingdao during this haze event were (2.8±0.9) ng/m3 and (245±174) pg/m3, respectively. On haze days (January 14 and 15), there was a negative correlation between TGM and PHg, and TGM/PHg ratios were higher than that on non-haze days (January 16 and 17), indicating that meteorological conditions would promote the transformation of TGM to PHg. Correlation analysis between mercury concentrations and environmental factors showed that both TGM and PHg were positively correlated with temperature and relative humidity, and negatively correlated with wind speed. TGM was positively correlated with SO2 and NO2, suggesting fossil fuel combustion was its major source. The pathways of air masses associated with the mercury samples were classified into 5 categories based cluster analysis. Atmospheric mercury in Qingdao during this event was mainly influenced by short-range transport, the influence of local pollution from Shandong area contributed to the highest TGM and PHg contents on haze days.